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1.
1IntroductionSincethe1970s,theCFCsandHalonsemitedbyhumanhavebeenwidelythoughtassubstanceswhichmaycauseozonedepletioninstrato...  相似文献   

2.
不同种类有机肥施用对稻田CH4和N2O排放的综合影响   总被引:19,自引:4,他引:15  
以麦茬稻田为对象,研究基肥施用不同有机肥对稻田CH4和N2O排放的综合影响.结果表明:有机肥施用对稻田CH4和N2O排放的季节变化模式无明显影响,但影响其排放量.与施用化肥(化肥处理)相比,施用菜饼+化肥(菜饼处理)促进CH4和N2O的排放,其季节排放总量分别增加了252%和22%;施用小麦秸秆+化肥(秸秆处理)和牛厩肥+化肥(牛厩肥处理)明显增加CH4排放,增加量分别为250%和45%,同时却减少N2O排放,分别减少18%和21%;施用猪厩肥+化肥(猪厩肥处理)降低CH4和N2O的排放,分别降低4%和18%.对CH4和N2O排放的综合温室效应分析表明,菜饼和秸秆处理的全球增温潜势(GWP)约为化肥处理的2.5倍,牛厩肥和化肥处理基本持平,但施用猪厩肥可减少10%~15%.各处理的GWP从高到低依次为菜饼、秸秆、牛厩肥、化肥和猪厩肥.单位产量的GWP以秸秆处理最高,菜饼次之,牛厩肥比化肥处理略高,猪厩肥处理最低.从本生长季来看,猪厩肥的施用对于实现环境效益与生产效益的协调发展具有一定作用.  相似文献   

3.
Gene therapy provides a mutation-independent approach to treat or even cure CF airway disease. To develop a clinical candidate for CF gene therapy, a thorough examination of preclinical efficacy in relevant cell and animal models is a prerequisite. For a long time, the CF field was struggling with a lack of appropriate animal models for CF airway pathology. Since 2008, many different and complementary animal models have been generated that develop hallmarks of CF airway disease, including the CF pig, ferret, and rat. With this, a new era has arisen that allows investigating the efficacy of gene therapy beyond molecular and electrophysiological end-points. Successful gene therapy most likely requires an appropriate time window. CF lung pathology progresses with age and therefore an early treatment would be beneficial to prevent irreversible damage. In that regard, newborn screening programs and prenatal diagnosis already provide a basis to facilitate future preventive gene-based treatment. If successful, gene therapy for CF airway disease would markedly reduce the treatment burden and improve life quality and life expectancy of CF patients.  相似文献   

4.
通过电化学的方法制备了经2-蒽醌磺酸钠(AQS)和聚苯胺(PANI)修饰的碳毡(CF)电极,探究其作为阴极应用于电芬顿系统中降解有机污染物的特征和影响因素及电化学稳定性.实验结果表明:经AQS/PANI修饰后碳毡阴极的电子转移内阻显著降低,仅为未修饰碳毡电极的0.21%,电化学活性显著提高.相同实验条件下修饰后的电极产过氧化氢的量约是未修饰电极的10倍.在阴极电位为-0.5 V,pH值为2以及Fe2+浓度为0.1 mmol·L-1的条件下,60 min内罗丹明B的降解率可达96.46%.而在同样的实验条件下,CF、AQS/CF和PANI/CF分别作为阴极时,电芬顿体系对于罗丹明B的降解率分别为24.57%、64.29%和72.97%,均低于AQS/PANI/CF阴极.在此基础上,进一步开展自由基的淬灭实验和EPR实验,结果表明经AQS/PANI修饰后的碳毡阴极可有效催化还原分子氧产生超氧自由基,超氧自由基进一步转化为芬顿反应过程中所需的过氧化氢.  相似文献   

5.
稻田不同种类有机肥施用对后季麦田N2O排放的影响   总被引:2,自引:0,他引:2  
以稻麦轮作系统为对象,研究水稻生长季基肥施用不同有机物料对后季麦田N2O排放及年轮作系统CH4和N2O综合温室效应的影响.结果表明:与施用化肥(化肥处理)相比,施用菜饼加化肥(菜饼处理)对后季麦田N2O排放量无影响;施用小麦秸秆加化肥(小麦秸秆处理)导致后季麦田的N2O排放量减少15%;施用牛厩肥加化肥(牛厩肥处理)和猪厩肥加化肥(猪厩肥处理)分别增加29%和16%.就稻麦年轮作生长季总体而言,菜饼、牛厩肥和猪厩肥处理稻麦生长季N2O排放总量较化肥处理分别增加6%、17%和7%,然而,小麦秸秆处理N2O排放总量减少16%.20a或500a时间尺度上各处理稻田CH4排放和该轮作周期水稻和小麦生长季N2O排放的总GWP值由大到小的顺序分别为:菜饼处理>小麦秸秆处理>牛厩肥处理>猪厩肥处理>化肥处理或菜饼处理>牛厩肥处理>猪厩肥处理>小麦秸秆处理>化肥处理.单位产量的GWP以作物残体处理最高,农家肥其次,化肥处理最低.因此,稻田基施不同种类有机物料都相应地增加稻麦轮作系统CH4和N2O排放的综合温室效应.  相似文献   

6.
本研究收集整理近10年来我国地市年鉴化肥施用数据,基于生命周期分析思想定量研究我国2008~2017年地市尺度的化肥施用碳足迹时空演变特征.结果表明:2008~2017年,我国化肥施用碳足迹以2013年为节点呈现"先增大后减少"的单峰变化,2015年我国氮、磷和钾肥施用总碳足迹负荷为1.97t CO2eq/hm2,较发达国家平均水平高出50%以上;在化肥生产和施用的全生命周期阶段,生产和运输过程的温室气体排放占比较高(60%以上);氮肥的施用贡献了约91%的总化肥施用碳足迹;超过3/4的地市化肥施用碳足迹负荷过高,主要位于我国三大粮食主产区(华北平原,东北平原和长江中下游平原);2013年以后仍有33个地市的化肥施用碳足迹依然保持增长,这些地区主要位于新疆,云南和黑龙江等地.本研究揭示了近10年我国化肥施用碳足迹的变化过程,可为我国绿色农业发展和温室气体相关政策制定提供一定参考依据.  相似文献   

7.
From a total of 490 cystic fibrosis (CF) high-risk families under supervision (mostly Russian Slavs from the European part of the country), DNA data including both direct screening for some CF gene(CFTR)mutations(deIF508, G551D and 1677delTA) and allelic polymorphism studies with tightly CF linked DNA markers were collected from 261 families. All full families (129) and 86 CF families with a deceased index child were found to be either fully (42 per cent) or partially (40 per cent) informative for DNA analysis. Prenatal diagnosis (PD) was carried out in 161 CF families. Microvillar enzyme (MVE) assay was applied to all 140 PD at the second trimester either as a single test (88) or in conjunction with DNA analysis (52). The frequency of false-negative results of the MVE assay was 1.3 percent and that of false-positive results, as judged by the albumin meconium test, was 5.0 per cent. Ambiguous results of MVE analysis were found in 30 cases, 12 of which were verified by DNA analysis. Molecular diagnosis of CF at the first trimester was carried out in 21 cases and four pregnancies were terminated. Altogether, 39 pregnancies with a predicted high risk of CF fetuses were terminated. The low average frequency of delF508 in CF chromosomes of Russian Slavs (50 per cent), its remarkable inter-population variation, and the significant proportion of at-risk families without an affected child determine the necessity of combined molecular and biochemical (MVE assay) approaches for efficient prenatal diagnosis of CF in the former U.S.S.R.  相似文献   

8.
采用大田试验方法,研究了5龄大棚土壤在不施肥(CK)、常规施肥(C14)、混合秸秆粉(CF)和褐煤粉(MF)4种处理下对土壤水溶性氮、磷调控的影响。结果表明,在不影响作物产量的前提下,CF、MF和CK与CH相比均能降低土壤水溶性氮含量水平,而CF、MF可促进土壤水溶性磷解吸;CF、MF与CK相比,CF促进土壤水溶性磷的释出,MF抑制了土壤水溶性磷的释出。  相似文献   

9.
炭纤维生物膜载体在反硝化脱氮中的应用   总被引:8,自引:0,他引:8       下载免费PDF全文
通过对反硝化微生物在炭纤维与聚丙烯、泡沫聚氨酯塑料类载体上的固着化实验,发现反硝化微生物在炭纤维载体上附着强度较大,而且每克炭纤维上的生物膜干重及对硝态氮处理能力是每克塑料类载体的200倍以上.PAN基高强度炭纤维比活性炭纤维能固着更多的反硝化微生物,这与高强度炭纤维载体与微生物的有效接触面积大、传质好及表面官能团有关.适量的表面含氧官能团能使较多的反硝化菌较牢固地吸附在炭纤维载体上.PAN基高强度炭纤维是一种生物相容性好、固着强度高、耐微生物分解及化学腐蚀的优异的反硝化菌新型固着化载体.  相似文献   

10.
Intestinal disaccharidases in amniotic fluid were studied in 41 pregnancies with a recurrence risk for cystic fibrosis (CF). In 11 out of 13 pregnancies with CF fetuses the maltase and sucrase activities were either below the control range (8 cases) or below the 10th percentile of control values (3 cases). Trehalase and lactase were slightly less informative indicators of CF. Of the other 28 pregnancies 3 had low amniotic fluid activities of several intestinal enzymes and were terminated, 12 resulted in the birth of a healthy child and 13 are continuing. The findings in fetal CF suggest an impairment of the defaecation of intestinal contents into the amniotic fluid. Reduced or low amniotic fluid disaccharidase activities were also found in other fetal disorders with demonstrated or presumed intestinal anomalies: e.g. anal atresia (2 cases), anencephaly (3 our of the 7 cases), trisomy 13 (5 cases), trisomy 18 (3 of the 5 cases) and trisomy 21 (19 of the 22 cases). Reduced amniotic fluid disaccharidase activities, although not specific for CF, are highly informative in pregnancies at high risk for CF. Using the 10th percentile of the normal range for amniotic fluid disaccharidase activities as an action line, the sensitivity of CF detection is estimated at 80 to 90 per cent, which could in high risk pregnancies reduce the risk of having another affected child from 1 in 4 to 1 in 20.  相似文献   

11.
外加气体对等离子体降解CF_2ClBr的影响   总被引:1,自引:0,他引:1  
用等离子体处理难降解大气污染物是近年国内外研究较活跃的领域,选用化学方法难降解的CF2CIBr为对象,研究了He、N2、O2及空气对等离子体降解CF2ClBr的影响,实现了CF2ClBr的常压解离.外加气体为He、N2时CF2ClBr的降解情况与纯CF2ClBr的降解基本相同,外加气体为O2、空气时主要降解产物为CF2O,Br2,Cl2外加气体对降解的影响大小为He<N2<O2,空气.  相似文献   

12.
为了研究磺胺类兽药抗生素对麦田NH3挥发的影响,采用了田间原位观测试验,对比分析了不同浓度磺胺二甲嘧啶(SMZ)在不同氮肥类型条件下对麦田NH3挥发的影响.试验共设9个处理,分别为:无氮肥无抗生素(CK);复合肥为基肥,分别加施0,5,15,30mg/kg土的磺胺二甲嘧啶处理(CF、CF+SMZ5、CF+SMZ15、CF+SMZ30);猪粪为基肥,分别加施0,5,15,30mg/kg土的磺胺二甲嘧啶处理(CM、CM+SMZ5、CM+SMZ15、CM+SMZ30).所有施肥处理追肥均为尿素.结果表明:基肥阶段各处理之间的NH3挥发速率无显著差异(P > 0.05),追肥阶段各处理之间有极显著差异(P<0.01),中高浓度SMZ表现为明显的促进作用(P<0.05).整个观测期,CF、CF+SMZ5、CF+SMZ15、CF+SMZ30和CM、CM+SMZ5、CM+SMZ15、CM+SMZ30处理的NH3-N损失百分比分别为5.5%、6.6%、13.9%、10.7%、11.0%、12.4%、11.9%、16.9%,其中CF+SMZ15、CF+SMZ30和CM+SMZ30处理显著增加了NH3-N挥发累积量(P<0.05),其导致的NH3-N损失比分别是同种基肥零抗生素添加的2.5、2.0和1.5倍,表明磺胺二甲嘧啶与复合肥的混施对土壤NH3挥发的促进效应要高于与猪粪的同步混施.兽药抗生素对土壤NH3挥发的影响不容忽视.因此,需大力加强对兽药抗生素的管控,并进一步探明不同兽药抗生素对土壤NH3挥发的影响机制,为减缓兽用抗生素的环境污染生态效应作支撑.  相似文献   

13.
The potential value of microvillar enzymes in the prenatal diagnosis of cystic fibrosis (CF) has previously been demonstrated and is corroborated in the present comparative study. Maltase and alkaline phosphatase (ALP) activities were studied in the amniotic fluids of 57 pregnancies with a 1 in 4 risk for CF or with a known CF outcome and in 489 controls. A simple assay for maltase activity (MU-maltase) with the fluorogenic substate 4-methylumbelliferyl α-glucoside, offers great technical advantages and an at least equal detection rate of CF, when compared to the previously used test with maltose as substrate. Intestinal ALP was estimated either as phenylalanine inhibitable activity (PI-ALP) or as the proportions of residual activity in the presence of the inhibitors phenylalanine or homoarginine. MU-maltase and PI-ALP appeared the most successful methods: both tests were able to detect 14 of the 16 (88 per cent) pregnancies with fetal CF. Each of the two tests alone also allowed a correct prediction in 24 of the 25 pregnancies at risk but with normal outcome; however all 25 cases could be correctly predicted by a combined evaluation. It is suggested that more than one intestinal enzyme activity should be evaluated to allow optimal results in the prenatal monitoring of pregnancies at high risk for CF.  相似文献   

14.
为了提高微生物燃料电池的产电性能,采用电沉积法将石墨态氮化碳(g-C_3N_4)与氧化亚铜(Cu_2O)负载到碳毡(Carbon felt,CF)表面,制得g-C_3N_4/Cu_2O/CF光电极用于构建微生物燃料电池.通过场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、傅里叶变换红外光谱(FT-IR)、光生电流曲线(I-T)、线性扫描伏安曲线(LSV)对光电阴极进行光电性能测试,并在白光发光二极管(LED)辐照下研究了以Cu_2O/CF、g-C_3N_4/Cu_2O/CF为阴极光催化微生物燃料电池的产电性能.结果表明,g-C_3N_4/Cu_2O/CF电极中g-C_3N_4分布在Cu_2O之间;g-C_3N_4/Cu_2O/CF光电极能提高光利用率,与Cu_2O/CF光电极相比,光电流密度达到2700 mA·m~(-2),增长幅度达到125%;与Cu_2O/CF阴极微生物燃料电池相比,g-C_3N_4/Cu_2O/CF阴极微生物燃料电池具有更优的产电能力,在白光LED辐照下最大功率密度和光电流密度达到110.7 mW·m~(-2)和1102 mA·m~(-2),增长幅度达到16%和27%.  相似文献   

15.
A French couple with an individual risk of carrying the cystic fibrosis (CF) mutation of 1/2 sought genetic counselling. From the DNA haplotypes generated by XV-2c and KM-19 RFLPs, it could be deduced that only one subject was a carrier, lowering the risk of having a CF baby from 1/16 to 1/200. The strong linkage disequilibrium between these RFLPs and the CF allele observed in France reduced the risk to 1/1600.  相似文献   

16.
基于多区域投入产出(MRIO)的中国区域居民消费碳足迹分析   总被引:5,自引:3,他引:2  
近年来,居民消费活动和环境的关系逐渐受到关注,而与温室气体排放相关的研究更是其中的热点.因此,本文采用“居民消费碳足迹”概念来定义特定居民消费活动所导致的直接和间接温室气体排放的总和,主要包括CO2、CH4、N2O3种温室气体;构建了基于环境扩展的多区域投入产出(Multiregional input-output,MRIO)模型的碳足迹核算方法,并以2007年中国8个区域为例对其居民消费碳足迹的数量、构成、分布及转移进行了分析.结果显示,2007年全国居民消费碳足迹总量达到31.74亿t(以CO2当量计).此外,碳足迹还呈现出区域差异明显、间接排放大于直接排放、城乡差距过大等特征.人均碳足迹方面,发展水平较高的京津、东部沿海地区明显高于相对滞后的西北、西南区域.研究还对碳足迹的区域分布和转移进行了深入探讨.结果发现,东北、京津、西北和西南区域转移收支为负,表示这些区域为其他区域承担的排放大于其他区域为其承担的排放;剩余的北部沿海、东部沿海、南部沿海和中部区域情况则正好相反.这些结果对现阶段中国制定具体区域消费政策或分配碳减排责任等具有参考价值;本研究的方法论也适用于研究其他环境因子及足迹因子与居民消费的关系.  相似文献   

17.
Thermal remediation of the soil contaminated with crude oil using microwave heating enhanced by carbon fiber (CF) was explored. The contaminated soil was treated with 2.45 GHz microwave, and CF was added to improve the conversion of microwave energy into thermal energy to heat the soil. During microwave heating, the oil contaminant was removed from the soil matrix and recovered by a condensation system of ice-salt bath. The experimental results indicated that CF could e ciently enhance the microwave heating of soil even with relatively low-dose. With 0.1 wt.% CF, the soil could be heated to approximately 700°C within 4 min using 800 W of microwave irradiation. Correspondingly, the contaminated soil could be highly cleaned up in a short time. Investigation of oil recovery showed that, during the remediation process, oil contaminant in the soil could be e ciently recovered without causing significant secondary pollution.  相似文献   

18.
A series of proteins (albumin, transferrin, a1- antitrypsin, alpha-fetoprotein and pancreatic oncofetal antigen) and enzymes (γ-glutamyltranspeptidase, aminopeptidase M, alkaline phosphatase, a-glucosidase and protease) was measured in fetal meconium extracts. There were 19 fetuses thought to have cystic fibrosis (CF), 13 with neural tube defects, three with chromosome abnormalities and 19 normal controls, all with gestational ages between 18 and 21 weeks. With the exception of alpha-fetoprotein, all the proteins and enzymes were significantly elevated in the CF meconium extracts. The most definitive indicator of a CF fetus was the albumin concentration, where the mean level was five times that found in the control groups. However, five of 19 fetuses assumed to have CF had albumin in the normal range. In these cases the meconium protease levels were grossly elevated. Furthermore, in the same five fetuses meconium concentration of pancreatic oncofetal antigen, a protein synthesized in the fetal pancreas, was also greatly raised. We suggest that post-mortem examination of a fetus thought to have CF should include measurement of meconium albumin, protease and pancreatic oncofetal antigen.  相似文献   

19.

Objectives

Cystic fibrosis (CF) is one of the most common severe autosomal recessive disorders. Prenatal or preconception CF screening is offered in some countries. A maternal blood sample in early pregnancy can provide circulating trophoblasts and offers a DNA source for genetic analysis of both the mother and the fetus. This study aimed to develop a cell-based noninvasive prenatal test (NIPT) to screen for the 50 most common CF variants.

Methods

Blood samples were collected from 30 pregnancies undergoing invasive diagnostics and circulating trophoblasts were harvested in 27. Cystic fibrosis testing was conducted using two different methods: by fragment length analysis and by our newly developed NGS-based CF analysis.

Results

In all 27 cases, cell-based NIPT provided a result using both methods in agreement with the invasive test result.

Conclusion

This study shows that cell-based NIPT for CF screening provides a reliable result without the need for partner- and proband samples.  相似文献   

20.
Inexpensive and accurate carrier testing for cystic fibrosis (CF) will be possible in the near future. There are no existing studies on the attitudes of English persons in the community to carrier testing for CF or any other recessive disorder. We have conducted a trial study of 166 persons at two schools, two doctors' surgeries, and a family planning clinic. Only a minority had clear pre-existing knowledge of cystic fibrosis and its genetic nature. However, over 80 per cent of those questioned expressed interest in knowing their carrier status. Although it is well known that uptake can only be assessed when a service is in place, and while further studies are required to confirm that testing will be of interest to couples of reproductive age with no previous knowledge of CF, the data strongly suggest that there will be interest in communitywide testing for CF carrier status when such a test becomes available in the United Kingdom.  相似文献   

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